Who is Lolek and Lonia from The Complete Maus and what is their importance?

Lonia is Anja’s niece. Her Aunt Tosha poisons (she dies) her to prevent the Nazis from taking her away during the evacuation of Zawiercie.

Lolek is Vladek's nephew and Uncle Herman's son. Lolek lives with Anja's family for much of the initial German occupation, first at Anja's father's house and then in the Srodula ghetto. Lolek tires of hiding and gives himself up to be sent to Auschwitz. He eventually survives and becomes a college professor.